In recent years, many utility lines have been laid or replaced by use of a horizontal boring or drilling machine which eliminates the need to dig a trench from the surface to install or replace the utility. This technique has generally come to be known as trenchless technology.
In a typical horizontal boring operation or a horizontal drilling operation, as it may alternatively be called, a bore hole is formed through the soil with a steerable bit connected to a drill string. The bore hole is commonly used to pull in a utility service such as an electric cable or a water line. The boring machine is mounted at the surface. One hydraulic motor on the boring machine causes the drill bit and drill string to rotate while another thrusts the drill bit and drill string forward as the bore is formed. It is also common to backream the bore with the machine, rotating a backreaming tool while drawing back the drill string to the boring machine.
The drill string is formed of a plurality of individual pipe sections threaded together. As the machine initially bores the hole, additional pipe sections must be added or “made up” as the bore is lengthened. The pipe sections are added from a magazine adapted to store a plurality of pipe sections. The pipe sections are transported from the magazine by a pipe handling device to the boring machine to form the drill string.
However, at times, while performing a bore with the boring machine, the magazine may be consumed such that all pipe sections will be used in the bore. When this occurs, a number of additional pipe sections may be required to complete the bore. One typical method for current pipe handling devices require that the empty magazine be removed from the drilling machine and another magazine with additional pipe sections be installed. This requires the use of additional equipment such as a tractor with a backhoe attachment to physically handle and replace the heavy magazine. This additional equipment is costly and may not be readily available at all times resulting in a delay in completing the job. Additionally, only a small number of additional pipe sections may be required to complete the bore, thus making it even less cost efficient to replace the entire magazine.
The invention of the U.S. Pat. No. 6,085,852 discloses a device that permits the operator to manually load and unload pipe sections without removing the magazine from the pipe handling device during boring and backreaming respectively. In this invention, the pipe holding mechanism of the pipe handling device is retracted to a position past the farthermost column of the magazine in order to manually load or unload pipe sections from the horizontal boring machine during boring and backreaming respectively. However, the device of U.S. Pat. No. 6,085,852 requires a large workspace area to provide for the retraction of the pipe holding mechanism beyond the farthermost column of the magazine.
The present invention provides a mechanism for adding and removing additional pipe sections from the horizontal boring machine in a compact work space. Additionally, the present invention provides a simple mechanism to easily manually load or unload an individual pipe section to or from the magazine, using the pipe handling assembly. In the case of adding a pipe section, the pipe section may be added to an empty magazine or to a selected magazine column using the present inventive device. The boring machine operator can then operate the pipe handling device to deliver the added pipe section to the drilling machine. Yet, at other times it may be desirable to remove a particular pipe section from the drill string. This can be accomplished in a cost effective manner using the present invention and without emptying the entire magazine as will be discussed. The present invention may be used with a pipe handling system such as that disclosed in U.S. Pat. No. 6,085,852, entitled Pipe Handling Device and issued Jul. 11, 2000, the contents of which are incorporated herein by reference.